Answer:The solution turn cloudy due to the formation of elemental sulphur as precipitate.
Step-by-step explanation:
Nitric acid is a very good oxidizing agent and it oxidizes sodium thiosulphate
into sodium sulphate.
The following reaction takes place when nitric acid reacts with sodium thiosulphate.
Na₂S₂O₃+2HNO₃→Na₂SO₄+S+2NO₂+H₂O
On reaction of sodium thiosulphate with nitric acid the following products are obtained:
1.Sodium sulphate(Na₂SO₄)
2.Precipitate of elemental sulphur(S)
3. Nitrogen dioxide (NO₂)
4.water molecule(H₂O)
The overall solution turns cloudy because of the formation of elemental sulphur as precipitate.